<p>A clear and lucid understanding of patterns and trends in sunshine duration is crucial for its application in energy research and climate prediction. This study employed the Mann–Kendall (MK) test and Innovative Trend Analysis (ITA) to assess trends in monthly, seasonal, and annual sunshine duration data from 1985 to 2022 across 25 stations in Bangladesh. Simultaneously, the Inverse Distance Weighting (IDW) method was utilized to analyze the spatial distribution of the sunshine duration patterns and trends. The study found that sunshine duration varies notably across seasons and months, with the longest durations observed in post-monsoon periods and in March. The results also revealed that most stations exhibited significant (p &lt; 0.01 or p &lt; 0.05) decreasing trends in monthly, seasonal, and annual data series using both MK and ITA tests. Spatially, the northwestern region showed significant decreasing trends, while the mid-southern region experienced significant increasing trends in seasonal and annual data series at p &lt; 0.01 or p &lt; 0.05. The observed increasing trends during the monsoon season and decreasing trends in the post-monsoon season may be attributed to seasonal shifts and climate change, while anthropogenic aerosol loading plays a significant role in the decreasing trends. The findings of this study provide valuable insights that can help decision-making and strategy development in sectors such as energy planning, agriculture, water management, and climate change mitigation.</p>